The present invention relates to a process for eliminating the defect of uncooked cheese curd in process cheese. More particularly, the present invention provides a process for the manufacturing of cheese to be used as an ingredient in processed cheese from pre-acidified fortified milk resulting in a curd that is an improved ingredient for the manufacture of process cheese. Pre-acidification reduces cheese calcium, conditioning the cheese proteins such that the cheese is easily and completely converted into a continuous molten process cheese with the addition of emulsifying salts and heat.
Cheese for use as an ingredient in process cheese is typically made by developing acidity in milk with starter cultures and coagulated with a clotting agent such as rennet. The cheese milk can be fortified with dairy solids (ultra-filtered milk, milk protein concentrate, non-fat dry milk, skim, part skim or whole milk condensed) and has been utilized for many years to improve plant throughput thus improving plant efficiency. After the milk has been set with a coagulant it is cut and then whey is separated from the resulting curd. The curd is pressed into a useable form and the separated whey is generally further processed for protein and fat recovery. The formed curd may be used to prepare process cheese type products by grinding and then heating the curd with an emulsifying salt(s).
The label name given to the resulting process cheese type products depends on its ingredients, process and composition and is defined by the U.S. Food and Drug Administration 21 CFR §§133.169-180. The term “pasteurized process cheese” refers to a food prepared by comminuting and mixing with the aid of heat a blend of cheeses, emulsifying salts, water, milkfat and optional colorings or flavorings into a homogeneous plastic mass. The term “pasteurized process cheese food” refers to a product that is similar in nature to pasteurized process cheese but may contain optional dairy ingredients. The maximum moisture level in a cheese food is 44% and the minimum fat level is 23%. The term “pasteurized process cheese spread” refers to a product that is similar in nature to a cheese food but may contain optional ingredients such as gums and sweetening agents. The maximum moisture level in a cheese spread is 60% and the minimum fat level is 20%. Pasteurized process cheese, cheese food and cheese spread are commonly referred to as “standardized products” meaning that they adhere to the Federal Standards of Identity as spelled out in the Code of Federal Regulations.
As used herein, the term “process cheese products” includes those products known and referred to as “pasteurized process cheese”, “pasteurized process cheese food”, “pasteurized process cheese spread”. In addition, “process cheese products” include all types of products that resemble standardized process cheese in flavor and/or texture but do not meet the guidelines in the Code of Regulations regardless of reason. This includes products that do not meet the compositional requirements or that contain ingredients that are not provided for in 21 CFR §§133.169-180.
Acidification of milk prior to cheesemaking has been well documented. For example, Reddy et al. patent (U.S. Pat. No. 4,959,229) discusses acidification of milk after pasteurization in conjunction with elevated pasteurization temperatures of 185° F. for 16 seconds as having a significant effect on increasing whey protein retention. Acidification of cheese milk was between pH 5.7 and 6.4.
The Brown el al. patent (U.S. Pat. No. 5,130,148) also discusses acidification as a method to avoid an acid coagulum that is weak and prone to shattering.
The Ernstrom et al. patent (U.S. Pat. No. 4,689,234) discusses the use of acidification as a method to facilitate calcium removal during ultra-filtration and dia-filtration steps when milk is acidified to a pH range of 5.6-6.2. Milk is concentrated until the ultra-filtered retentate comprises 15-30% of the original weight then acidified by an acid or acid producing material to a pH of about 4.9-5.6. Following fermentation a coagulant is added for curd development.
The Foster et al. patent (U.S. Pat. No. 3,172,767) discuss adjusting downwardly the pH of whole milk indicating an improvement in the curd and clarity of the whey as the acidity of the milk was increased. Milk is acidified using a food grade acid to not lower than pH 4.6. The milk is then pasteurized and coagulated at 85-180° F.